Optical information apparatus and information recording or reproducing method

Abstract

An optical head ( 10 ) focuses and irradiates a servo light beam onto at least one servo layer, and focuses and irradiates a recording/reproducing light beam onto a plurality of recording layers. An initial recording unit ( 20 ) records layer position information for specifying a position of each recording layer in advance in a predetermined position of each recording layer before recording user data in use of the recording/reproducing light beam, a layer position detection unit ( 21 ) reads layer position information in a predetermined recording layer by using the recording/reproducing light beam, and detects which one of the plurality of recording layers is the predetermined recording layer where the focal point of the recording/reproducing light beam is positioned, based on the read layer position information, and a seeking unit ( 22 ) moves the focal point of the recording/reproducing light beam to a target position based on the detected layer position.

1 . An optical information apparatus for recording or reproducing information to/from an information carrier provided with a plurality of recording layers on which information is recorded and at least one servo layer which is used for servo control,
 the apparatus comprising:   a focused irradiation unit that focuses and irradiates a servo light beam onto at least one servo layer, and focuses and irradiates a recording/reproducing light beam onto the plurality of recording layers;   a layer position information recording unit that records layer position information for specifying a position of each recording layer in a predetermined position of each recording layer in advance before recording user data, in use of the recording/reproducing light beam which is focused and irradiated by the focused irradiation unit;   a layer position detection unit that reads the layer position information recorded by the layer position information recording unit in a predetermined recording layer by using the recording/reproducing light beam, and detects, based on the read layer position information, which one of the plurality of recording layers is the predetermined recording layer where the focal point of the recording/reproducing light beam is positioned; and   a moving unit that moves the focal point of the recording/reproducing light beam to a target position based on the layer position detected by the layer position detection unit.   
     
     
         2 . The optical information apparatus according to  claim 1 , further comprising a radius position error detection unit that detects an error of a position of the recording/reproducing light beam in the radius direction, wherein
 the layer position information recording unit determines a width in a tracking direction of the recording area for recording the layer position information in the predetermined position of each recording layer in advance, based on the error detected by the radius position error detection unit.   
     
     
         3 . The optical information apparatus according to  claim 2 , further comprising a mechanical error amount holding unit that holds a mechanical error amount in the radius direction, which is generated when the focal point of the recording/reproducing light beam is moved in the radius direction, wherein
 the radius position error detection unit detects an error of the position of the recording/reproducing light beam in the radius direction based on the error amount held in the mechanical error amount holding unit.   
     
     
         4 . The optical information apparatus according to  claim 2 , further comprising a tilt radius error amount holding unit that holds an error amount of the focal point of the recording/reproducing light beam in the radius direction, which is generated by a relative tilt between an optical axis of the recording/reproducing light beam, which is parallel with the optical axis of the servo light beam, and the information carrier, in a state where the focal point of the servo light beam is controlled to be positioned on a predetermined track of the servo layer, wherein
 the radius position error detection unit detects an error of the position of the recording/reproducing light beam in the radius direction based on the error amount held in the tilt radius error amount holding unit.   
     
     
         5 . The optical information apparatus according to  claim 2 , wherein
 the radius position error detection unit detects an error of a position of the recording/reproducing light beam in the radius direction that is common to all the recording layers.   
     
     
         6 . The optical information apparatus according to  claim 2 , wherein
 the radius position error detection unit detects an error of a position of the recording/reproducing light beam in the radius direction for each recording layer.   
     
     
         7 . The optical information apparatus according to  claim 1 , wherein
 the layer position information recording unit records the layer position information in advance in a same radius position in each recording layer.   
     
     
         8 . The optical information apparatus according to  claim 1 , further comprising a layer position information recording determination unit that determines whether there is a recording layer where the layer position information is not recorded by the layer position information recording unit, wherein
 when the layer position information recording determination unit determines that there is a recording layer where the layer position information is not recorded, the layer position information recording unit records the layer position information in a predetermined position of the recording layer where the layer position information is not recorded.   
     
     
         9 . The optical information apparatus according to  claim 8 , further comprising an end layer detection unit that detects that the focal point of the recording/reproducing light beam has exceeded an upper end recording layer or a lower end recording layer of the plurality of recording layers, wherein
 when the layer position information recording unit records the layer position information in the upper end recording layer or the lower end recording layer, the layer position information recording determination unit determines that there is a recording layer where the layer position information is not recorded in a case where the end layer detection unit detects that the focal point of the recording/reproducing light beam exceeded the upper end recording layer or the lower end recording layer of the plurality of recording layers before reaching the target recording layer.   
     
     
         10 . The optical information apparatus according to  claim 9 , further comprising a focus error detection unit that detects a displacement signal in accordance with a displacement of a focal point of the recording/reproducing light beam with respect to the plurality of recording layers or at least one servo layer of the information carrier, wherein
 when the focal point of the recording/reproducing light beam is moved to a target recording layer by the moving unit, the end layer detection unit detects that the focal point of the recording/reproducing light beam has exceeded the upper end recording layer or the lower end recording layer of the plurality of recording layers, based on the displacement signal detected by the focus error detection unit.   
     
     
         11 . The optical information apparatus according to  claim 9 , further comprising a servo layer determination unit that determines whether the focal point of the recording/reproducing light beam is in the recording layer or the servo layer based on a reflected light quantity, wherein
 when the servo layer determination unit determined that the focal point of the recording/reproducing light beam is in the servo layer, the end layer detection unit detects that the focal point of the recording/reproducing light beam has exceeded the upper end recording layer or the lower end recording layer of the plurality of recording layers.   
     
     
         12 . The optical information apparatus according to  claim 8 , further comprising a recording state determination unit that focuses and irradiates the recording/reproducing light beam on all of the plurality of recording layers respectively after the layer position information recording unit records the layer position information in each recording layer in advance, and determines whether each recording layer is in a recorded state or an unrecorded state based on the reflected light quantity received from each recording layer, wherein
 when the recording state determination unit determines that at least one recording layer is in an unrecorded state, the layer position information recording determination unit determines that there is a recording layer where the layer position information is not recorded.   
     
     
         13 . The optical information apparatus according to  claim 1 , further comprising:
 a layer position reading unit that reads the layer position information recorded in each recording layer by the layer position information recording unit; and   a layer position conversion information generation unit that generates layer position conversion information in which layer position information read by the layer position reading unit and an actual position of the recording layer are associated with each other, wherein   the moving unit converts the layer position information detected by the layer position detection unit into the actual recording layer position by using the layer position conversion information generated by the layer position conversion information generation unit, and moves the focal point of the recording/reproducing light beam to the target recording layer.   
     
     
         14 . The optical information apparatus according to  claim 7 , wherein
 the moving unit moves the focal point of the recording/reproducing light beam to the target recording layer in a radius position where the layer position information is recorded by the layer position information recording unit.   
     
     
         15 . The optical information apparatus according to  claim 14 , wherein
 the layer position information recording unit records in advance the layer position information in a plurality of radius positions of each recording layer.   
     
     
         16 . The optical information apparatus according to  claim 1 , further comprising:
 a termination position information holding unit that holds termination position information that indicates a termination position of user data recorded in the information carrier; and   a recording state information generation unit that generates, based on the termination position information held in the termination position information holding unit, recording state information that indicates a recording state of each recording layer in a radius position where the focal point of the recording/reproducing light beam is positioned, wherein   when the recording layer, where the focal point of the recording/reproducing light beam is positioned, is in an unrecorded state and the layer position detection unit cannot read the layer position information, the moving unit determines the direction to move the focusing direction of the focal point of the recording/reproducing light beam based on the recording state information generated by the recording state information generation unit.   
     
     
         17 . The optical information apparatus according to  claim 16 , wherein
 the user data is recorded sequentially from the upper end recording layer or the lower end recording layer out of the plurality of recording layers of the information carrier, and   the recording state information generation unit determines the recording state of each recording layer based on the termination position information held in the termination position holding unit.   
     
     
         18 . The optical information apparatus according to  claim 16 , wherein
 the termination position holding unit holds the termination position information for each recording layer, and   the recording state information generation unit determines the recording state of each recording layer based on the termination position information of each recording layer held in the termination position holding unit.   
     
     
         19 . The optical information apparatus according to  claim 1 , further comprising an inter-layer driving amount holding unit that holds a driving amount for controlling a distance between a focal point of the servo light beam and a focal point of the recording/reproducing light beam according to a distance between the servo layer and at least one of the plurality of recording layers, wherein
 when a position control of the focal point of the servo light beam and the focal point of the recording/reproducing light beam in the direction perpendicular to the recording surface of the information carrier is not performed, the moving unit moves the focal point of the recording/reproducing light beam according to the driving amount held in the inter-layer driving amount holding unit.   
     
     
         20 . The optical information apparatus according to  claim 19 , wherein the inter-layer driving amount holding unit holds the driving amount based on the pre-designed distance between the servo layer and each recording layer of the information carrier. 
     
     
         21 . The optical information apparatus according to  claim 19 , wherein
 when the focal point of the recording/reproducing light beam is focused and irradiated onto each recording layer, the inter-layer driving amount holding unit measures a driving amount to control a distance between the focal point of the servo light beam and the focal point of the recording/reproducing light beam in each recording layer, and holds the measured driving amount.   
     
     
         22 . The optical information apparatus according to  claim 1 , wherein
 the layer position information recording unit records the layer position information in the predetermined position of each recording layer in advance when the information carrier is shipped.   
     
     
         23 . The optical information apparatus according to  claim 1 , wherein
 the layer position information recording unit records the layer position information in the predetermined position of each recording layer in advance when the information carrier is started up for the first time.   
     
     
         24 . The optical information apparatus according to  claim 1 , wherein
 the layer position information recording unit records the layer position information in the predetermined position of each recording layer in advance when the user data is recorded on the information carrier for the first time.   
     
     
         25 . The optical information apparatus according to  claim 1 , wherein
 the layer position information recording unit records the layer position information in the predetermined position of one recording layer out of the plurality of recording layers of the information carrier in advance when the user data is recorded on this one recording layer for the first time.   
     
     
         26 . An information recording or reproducing method for recording or reproducing information to/from an information carrier provided with a plurality of recording layers on which information is recorded and at least one servo layer which is used for servo control,
 the method comprising:   a layer position information recording step of recording layer position information for specifying a position of each recording layer in a predetermined position of each recording layer in advance before recording user data, in use of a recording/reproducing light beam which is focused and irradiated onto the plurality of recording layers;   a layer position detecting step of reading the layer position information recorded in the layer position information recording step in a predetermined recording layer by using the recording/reproducing light beam, and detecting, based on the read layer position information, which one of the plurality of recording layers is the predetermined recording layer where the focal point of the recording/reproducing light beam is positioned; and   a moving step of moving the focal point of the recording/reproducing light beam to a target position based on the layer position detected in the layer position detecting step.